President Obama today outlined his plan to combat climate change, calling for new standards to reduce carbon pollution and saying he would not approve the Keystone XL oil pipeline if it produces more greenhouse gas emissions.

"As a president, as a father and as an American, I am here to say we need to act," the president told a crowd of roughly 500 people at Georgetown University. "I refuse to condemn your generation and future generations to a planet that's beyond fixing. And that's why today I'm announcing a new national climate action plan, and I'm here to enlist your generation's help in keeping the United States of America a leader, a global leader in the fight against climate change."

Obama's speech, which he delivered outside in the blistering heat, came four months after he urged lawmakers to come up with bipartisan solutions to climate change in his State of the Union address.

"I still want to see that happen. I'm willing to work with anyone to make that happen," he said. "But this is a challenge that does not pause for partisan gridlock."

In the meantime, the president is seeking to advance his climate agenda through a series of executive actions in an effort to side-step the gridlock in Congress.

Obama issued a directive to the EPA to draft carbon pollution standards for both new and existing power plants.

"Right now, there are no federal limits to the amount of carbon pollution that those plants can pump into our air - none, zero," he said. "We limit the amount of toxic chemicals like mercury and sulfur and arsenic in our air or our water, but power plants can still dump unlimited amounts of carbon pollution into the air for free. That's not right, that's not safe and it needs to stop.

"For the sake of our children and the health and safety of all Americans, I'm directing the Environmental Protection Agency to put an end to the limitless dumping of carbon pollution from our power plants and complete new pollution standards for both new and existing power plants," he said to applause.

As the State Department comes under increasing pressure from Republicans and business leaders to approve the Keystone XL pipeline, Obama said the project should be allowed to move forward only if does not "significantly exacerbate the problem of carbon pollution."

"Allowing the Keystone pipeline to be built requires finding that doing so would be in our nation's interests," he said.

The president issued a stern warning to "doomsayers" who claim his proposals will harm the economy or who question the need to take action.

"We've got to move beyond partisan politics on this issue," he said.

"I don't have much patience for anyone who denies that this challenge is real. We don't have time for a meeting of the flat earth society," he said, reviving a line from his 2012 campaign. "Sticking your head in the sand might make you feel safer, but it's not going to protect you from the coming storm. And ultimately, we will be judged as a people and as a society and as a country on where we go from here."

The president's proposals are controversial. While the plan to reduce emissions from coal-fired power plants is being hailed by environmentalists, the opposition has already dubbed the plan "Obama's War on Coal."

"The regulations the president wants to force on coal are not feasible. And if it's not feasible, it's not reasonable," said Sen. Joe Manchin, D-W.Va. "It's clear now that the president has declared a war on coal. It's simply unacceptable that one of the key elements of his climate change proposal places regulations on coal that are completely impossible to meet with existing technology."

House Speaker John Boehner, R-Ohio, slammed the president's proposed regulations before Obama outlined them publicly.

"I think this is absolutely crazy," Boehner told reporters last week. "Why would you want to increase the cost of energy and kill more American jobs at a time when the American people are still asking the question: Where are the jobs?"